arm: mxs: ocotp: disable OCOTP clock after access is finished
[karo-tx-uboot.git] / drivers / misc / mxc_ocotp.c
1 /*
2  * (C) Copyright 2013 ADVANSEE
3  * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
4  *
5  * Based on Dirk Behme's
6  * https://github.com/dirkbehme/u-boot-imx6/blob/28b17e9/drivers/misc/imx_otp.c,
7  * which is based on Freescale's
8  * http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/tree/drivers/misc/imx_otp.c?h=imx_v2009.08_1.1.0&id=9aa74e6,
9  * which is:
10  * Copyright (C) 2011 Freescale Semiconductor, Inc.
11  *
12  * SPDX-License-Identifier:     GPL-2.0+
13  */
14
15 #include <common.h>
16 #include <fuse.h>
17 #include <asm/errno.h>
18 #include <asm/io.h>
19 #include <asm/arch/clock.h>
20 #include <asm/arch/imx-regs.h>
21
22 #define BO_CTRL_WR_UNLOCK               16
23 #define BM_CTRL_WR_UNLOCK               0xffff0000
24 #define BV_CTRL_WR_UNLOCK_KEY           0x3e77
25 #define BM_CTRL_ERROR                   0x00000200
26 #define BM_CTRL_BUSY                    0x00000100
27 #define BO_CTRL_ADDR                    0
28 #define BM_CTRL_ADDR                    0x0000007f
29
30 #define BO_TIMING_STROBE_READ           16
31 #define BM_TIMING_STROBE_READ           0x003f0000
32 #define BV_TIMING_STROBE_READ_NS        37
33 #define BO_TIMING_RELAX                 12
34 #define BM_TIMING_RELAX                 0x0000f000
35 #define BV_TIMING_RELAX_NS              17
36 #define BO_TIMING_STROBE_PROG           0
37 #define BM_TIMING_STROBE_PROG           0x00000fff
38 #define BV_TIMING_STROBE_PROG_US        10
39
40 #define BM_READ_CTRL_READ_FUSE          0x00000001
41
42 #define BF(value, field)                (((value) << BO_##field) & BM_##field)
43
44 #define WRITE_POSTAMBLE_US              2
45
46 static void wait_busy(struct ocotp_regs *regs, unsigned int delay_us)
47 {
48         while (readl(&regs->ctrl) & BM_CTRL_BUSY)
49                 udelay(delay_us);
50 }
51
52 static void clear_error(struct ocotp_regs *regs)
53 {
54         writel(BM_CTRL_ERROR, &regs->ctrl_clr);
55 }
56
57 static int prepare_access(struct ocotp_regs **regs, u32 bank, u32 word,
58                                 int assert, const char *caller)
59 {
60         *regs = (struct ocotp_regs *)OCOTP_BASE_ADDR;
61
62         if (bank >= ARRAY_SIZE((*regs)->bank) ||
63                         word >= ARRAY_SIZE((*regs)->bank[0].fuse_regs) ||
64                         !assert) {
65                 printf("mxc_ocotp %s(): Invalid argument\n", caller);
66                 return -EINVAL;
67         }
68
69         enable_ocotp_clk(1);
70
71         wait_busy(*regs, 1);
72         clear_error(*regs);
73
74         return 0;
75 }
76
77 static int finish_access(struct ocotp_regs *regs, const char *caller)
78 {
79         u32 err;
80
81         err = !!(readl(&regs->ctrl) & BM_CTRL_ERROR);
82         clear_error(regs);
83         enable_ocotp_clk(0);
84
85         if (err) {
86                 printf("mxc_ocotp %s(): Access protect error\n", caller);
87                 return -EIO;
88         }
89
90         return 0;
91 }
92
93 static int prepare_read(struct ocotp_regs **regs, u32 bank, u32 word, u32 *val,
94                         const char *caller)
95 {
96         return prepare_access(regs, bank, word, val != NULL, caller);
97 }
98
99 int fuse_read(u32 bank, u32 word, u32 *val)
100 {
101         struct ocotp_regs *regs;
102         int ret;
103
104         ret = prepare_read(&regs, bank, word, val, __func__);
105         if (ret)
106                 return ret;
107
108         *val = readl(&regs->bank[bank].fuse_regs[word << 2]);
109
110         return finish_access(regs, __func__);
111 }
112
113 static void set_timing(struct ocotp_regs *regs)
114 {
115         u32 ipg_clk;
116         u32 relax, strobe_read, strobe_prog;
117         u32 timing;
118
119         ipg_clk = mxc_get_clock(MXC_IPG_CLK);
120
121         relax = DIV_ROUND_UP(ipg_clk * BV_TIMING_RELAX_NS, 1000000000) - 1;
122         strobe_read = DIV_ROUND_UP(ipg_clk * BV_TIMING_STROBE_READ_NS,
123                                         1000000000) + 2 * (relax + 1) - 1;
124         strobe_prog = DIV_ROUND_CLOSEST(ipg_clk * BV_TIMING_STROBE_PROG_US,
125                                                 1000000) + 2 * (relax + 1) - 1;
126
127         timing = BF(strobe_read, TIMING_STROBE_READ) |
128                         BF(relax, TIMING_RELAX) |
129                         BF(strobe_prog, TIMING_STROBE_PROG);
130
131         clrsetbits_le32(&regs->timing, BM_TIMING_STROBE_READ | BM_TIMING_RELAX |
132                         BM_TIMING_STROBE_PROG, timing);
133 }
134
135 static void setup_direct_access(struct ocotp_regs *regs, u32 bank, u32 word,
136                                 int write)
137 {
138         u32 wr_unlock = write ? BV_CTRL_WR_UNLOCK_KEY : 0;
139         u32 addr = bank << 3 | word;
140
141         set_timing(regs);
142         clrsetbits_le32(&regs->ctrl, BM_CTRL_WR_UNLOCK | BM_CTRL_ADDR,
143                         BF(wr_unlock, CTRL_WR_UNLOCK) |
144                         BF(addr, CTRL_ADDR));
145 }
146
147 int fuse_sense(u32 bank, u32 word, u32 *val)
148 {
149         struct ocotp_regs *regs;
150         int ret;
151
152         ret = prepare_read(&regs, bank, word, val, __func__);
153         if (ret)
154                 return ret;
155
156         setup_direct_access(regs, bank, word, false);
157         writel(BM_READ_CTRL_READ_FUSE, &regs->read_ctrl);
158         wait_busy(regs, 1);
159         *val = readl(&regs->read_fuse_data);
160
161         return finish_access(regs, __func__);
162 }
163
164 static int prepare_write(struct ocotp_regs **regs, u32 bank, u32 word,
165                                 const char *caller)
166 {
167         return prepare_access(regs, bank, word, true, caller);
168 }
169
170 int fuse_prog(u32 bank, u32 word, u32 val)
171 {
172         struct ocotp_regs *regs;
173         int ret;
174
175         ret = prepare_write(&regs, bank, word, __func__);
176         if (ret)
177                 return ret;
178
179         setup_direct_access(regs, bank, word, true);
180         writel(val, &regs->data);
181         wait_busy(regs, BV_TIMING_STROBE_PROG_US);
182         udelay(WRITE_POSTAMBLE_US);
183
184         return finish_access(regs, __func__);
185 }
186
187 int fuse_override(u32 bank, u32 word, u32 val)
188 {
189         struct ocotp_regs *regs;
190         int ret;
191
192         ret = prepare_write(&regs, bank, word, __func__);
193         if (ret)
194                 return ret;
195
196         writel(val, &regs->bank[bank].fuse_regs[word << 2]);
197
198         return finish_access(regs, __func__);
199 }